SubReturnValue.pl - Example on Return Values

This section provides a tutorial example on how a list value can be returned from a subroutine to the caller using the return statement.

As mentioned in the previous section, all return values are passed back to the caller as a single list of scalars. If a list (array or hash) is used as a return value, it will be exploded into multiple return values with its elements.

Here is a tutorial example on how to return a list value to the caller:

#- SubReturnValue.pl
#- Copyright (c) 1995 by Dr. Herong Yang, http://www.herongyang.com/
#
   $a = 'hello';
   @a = ('mon','tue','wed','thu','fri');
   print &subReturnValue($a), "\n";
   print $a, "\n";
   print join(',',&subReturnValue(@a)), "\n";
   print join(',',@a), "\n";
   exit;
sub subReturnValue {
   my @l = @_;
   foreach (@l) {
      tr/a-z/A-Z/;
   }
   return @l;
}

Here is the output of the tutorial script:

HELLO
hello
MON,TUE,WED,THU,FRI
mon,tue,wed,thu,fri

The output clearly shows you that an array can be easily returned to the caller.

Table of Contents

 About This Book

 Perl on Linux Systems

 ActivePerl on Windows Systems

 Data Types: Values and Variables

 Expressions, Operations and Simple Statements

User Defined Subroutines

 Declaring and Calling Subroutines

 SubParamList.pl - Example on Parameter List

 SubParamAlias.pl - Example on Parameters as Alias

SubReturnValue.pl - Example on Return Values

 SubCalling.pl - Example on Calling Formats

 Perl Built-in Debugger

 Name Spaces and Perl Module Files

 Symbolic (or Soft) References

 Hard References - Addresses of Memory Objects

 Objects (or References) and Classes (or Packages)

 Typeglob and Importing Identifiers from Other Packages

 String Built-in Functions and Performance

 File Handles and Data Input/Output

 Open Files in Binary Mode

 Open Directories and Read File Names

 File System Functions and Operations

 Converting Perl Script to Executable Binary

 Using DBM Database Files

 Using MySQL Database Server

 Socket Communication Over the Internet

 XML::Simple Module - XML Parser and Generator

 XML Communication Model

 SOAP::Lite - SOAP Server-Client Communication Module

 Perl Programs as IIS Server CGI Scripts

 CGI (Common Gateway Interface)

 XML-RPC - Remote Procedure Call with XML and HTTP

 RPC::XML - Perl Implementation of XML-RPC

 Integrating Perl with Apache Web Server

 CGI.pm Module for Building Web Pages

 LWP::UserAgent and Web Site Testing

 References

 PDF Printing Version